Ryan Daniel Montgomery (born July 5, 1977), known professionally as Royce da 5'9" (or simply Royce 5'9"), is an American rapper. Best known for his association with fellow Detroit rapper Eminem, they became acquainted in 1997 and formed the hip hop duo, Bad Meets Evil the following year. Their 2011 single, "Lighters" (featuring Bruno Mars) peaked at number four on the Billboard Hot 100 and preceded the release of their debut extended play (EP), Hell: The Sequel (2011). The song and its parent EP, which debuted atop the Billboard 200, have yielded Montgomery's furthest commercial success.

Montgomery first embarked on a solo career with his debut studio album, Rock City in 2002; originally slated for release the year prior, disputes with Columbia Records led it to an independent release. He released eight follow-up studio albums to critical acclaim; his latest, The Allegory (2020), earned Montgomery his first Grammy Award nomination for Best Rap Album in 2021. He also formed the hip hop supergroup Slaughterhouse with Joe Budden, Joell Ortiz and Kxng Crooked in 2008. Active for a decade, the group released two studio albums—Slaughterhouse (2008) and Welcome to: Our House (2012)—to commercial success. In 2014, he formed the hip hop duo PRhyme in 2014, with producer DJ Premier; they have released two albums.[5]